Device for adapting narrowband voice traffic of a local access network to allow transmission over a broadband asynchronous transfer mode network

Abstract

A voice adaptation device (18) provides an interface between a narrowband local access network and a broadband asynchronous transfer mode (ATM) backbone network (16). The voice adaptation device (18) includes a T1/E1 network adaptor (50) that converts T1/E1 signals carrying narrowband voice traffic into an ATM cell format. The T1/E1 network adaptor (50) also performs echo cancelling, voice enhancement, digital voice protocol conversion, and compression/decompression on the narrowband voice traffic. The voice adaptation device (18) also includes a synchronous optical network formatter (52) that places ATM cells generated by the T1/E1 network adaptor (50) into synchronous optical network signals. The synchronous optical network signals are transmitted across the broadband ATM backbone network (16).

What is claimed is: 
     
       1. A device for adapting narrowband voice traffic of a local access network to allow transmission over a broadband asynchronous transfer mode network, comprising: a signal interface circuit operable to receive narrowband voice traffic from and send narrowband voice traffic to the local access network;   a transceiver circuit operable to provide framing and timing conversion functions to the narrowband voice traffic;   an echo canceler circuit operable to eliminate voice band echo from he narrowband voice traffic regardless of a transmission path over the broadband asynchronous transfer mode network;   a compressor circuit operable to compress and decompress the narrowband voice traffic in order to reduce a signal capacity transferred over the broadband asynchronous transfer mode network;   a cell adaptor circuit operable to convert the narrowband voice traffic to and from asynchronous transfer mode cells; and   a formatter circuit operable to transfer and receive synchronous optical network signals carrying said asynchronous transfer mode cells to and from the broadband asynchronous transfer mode network, respectively.   
     
     
       2. The device of claim 1, further comprising: a voice enhancer circuit operable to improve a signal quality of the narrowband voice traffic.   
     
     
       3. The device of claim 1, wherein said compressor circuit performs ADPCM compression on the narrowband voice traffic. 
     
     
       4. The device of claim 1, wherein said asynchronous transfer mode cells are routed across the broadband asynchronous transfer mode network through virtual path identifiers, said formatter circuit operable to adjust said virtual path identifiers of said asynchronous transfer mode cells in response to faults and congestion points within the broadband asynchronous transfer mode network. 
     
     
       5. The device of claim 1, wherein said cell adaptor circuit separates the narrowband voice traffic into individual voice channels in order to provide individual treatment for each voice channel. 
     
     
       6. The device of claim 5, wherein said cell adaptor circuit includes: a channel multiplexer operable to separate and combine individual voice channels;   a plurality of channel processors operable to convert each individual voice channel to and from asynchronous transfer mode cell format;   a plurality of channel processors operable to convert each individual digital voice protocol from one digital voice protocol to another digital voice protocol; and   a cell distribution unit operable to transfer asynchronous transfer mode cells to and from said plurality of channel processors.   
     
     
       7. A telecommunications network, comprising: a broadband asynchronous transfer mode backbone network:   a narrowband local access synchronous transfer mode network:   a voice adaptation device operable to interface voice traffic between said broadband asynchronous transfer mode backbone network and said narrowband local access synchronous transfer mode network wherein said voice adaptation device performs echo cancellation and voice enhancement on said voice traffic regardless of a transmission path of voice traffic over the broadband asynchronous transfer mode backbone network, wherein said voice adaptation device converts narrowband voice traffic of said narrowband local access synchronous transfer mode network into synchronous optical network signals carrying voice traffic in asynchronous transfer mode cell format for transmission across said broadband asynchronous transfer mode backbone network,   wherein said broadband asynchronous transfer mode backbone network transfers said synchronous optical network signals through a ring structure having a primary path and a secondary path; said voice adaptation device operable to adjust a virtual path identifier field that determines which of said primary and secondary paths is selected in response to fault indications and congestion detected by said ring structure and/or virtual path quality analysis software processing of said voice adaptation device.   
     
     
       8. The telecommunications network of claim 7, wherein said voice adaptation device is integrated with said broadband asynchronous transfer mode backbone network or said narrowband local access synchronous transfer mode network. 
     
     
       9. A method of interfacing voice traffic between a narrowband synchronous transfer mode network and a broadband asynchronous transfer mode network, comprising the steps of: receiving voice traffic from the narrowband synchronous transfer mode network;   performing framing and timing operations on the voice traffic to place the voice traffic into a broadband timing mode;   eliminating voice band echo from the voice traffic regardless of a transmission path through the broadband asynchronous transfer mode network;   compressing the voice traffic to reduce signal capacity across the broadband asynchronous transfer mode network:   converting the voice traffic into an asynchronous transfer mode cell format;   formatting the synchronous transfer mode cells onto synchronous optical network signals for transmission across the broadband asynchronous transfer mode network.   
     
     
       10. The method of claim 9, further comprising the step of: enhancing signal quality of the voice traffic.   
     
     
       11. The method of claim 9, further comprising the step of: receiving synchronous optical network signals from the broadband asynchronous transfer mode network;   extracting asynchronous transfer mode cells from the synchronous optical network signals;   transforming the asynchronous network signals into synchronous transfer mode voice traffic;   performing framing and timing operations on the voice traffic to place the voice traffic into a narrowband timing mode; and   transmitting the voice traffic across the narrowband synchronous transfer mode network.